Normal engine temps.

[Learn2surf]

3 hours ago, Steve B. said:

Good on you for watching the gauges like a hawk. I do too.

Steve B.

My husband thinks I’m nuts.  He thinks since the boat is new it should be perfect.  He’s a slow learner on these things.  I actually wonder how often other people check gauges...I probably check them too much.  But I don’t trust our boat yet;). 

[pauley71]

10 hours ago, hethj7 said:

Okay, I thought on this a little more.    I do think perhaps some degradation was happening due to slow priming which lead to slow failure.   The ultimate failure occurred when my wife was bringing the boat around from a ramp to a friend's slip, less than half a mile and probably barely above idle the whole time.  She called and said an exhaust manifold temp warning came on.    She was almost to the slip, so I told her to watch the temp on the screen and shut down if it hit 190, which it didn't before she got it in.   Thinking back on it, I think the impeller probably failed like some of the pics you can find on TMC, Facebook, etc. with a few failed vanes, etc.     I think once that happened, water flow started to stop, exhaust temps went up first, which cause the screen alarm she saw.    She then got it into the slip, basically at that point spinning the impeller dry before engine temps got too high, which may have resulted in the ultimate roasted treatment you see in my photo.   

The failure is bad impellers. The Sherwood 15000A had a bad batch and my dealer has moved to the 626. Of slow priming was the issue, then it would have issues with the new model as well. I also think rev’ing it wouldn’t help as now you are just turning more RPMs in a dry housing (if that’s a problem). 
My lake is nuclear and water temps hit 99 in the spot near the plant (we go up and “hot tub”). My temps on the M5di go from 165-174. 

[platon20]

I know this is an old thread but wanted to bump it back up.  I just bought a new Malibu but havent taken delivery yet.

I like the fact that Malibu's engines have the impeller at the top for easy service.

My question is this -- the Monsoon M5/M6 impeller location is ABOVE the water line, correct?

If that's the case, the impeller may take a few seconds to prime which would create extra stress on the impeller as it would turn several/dozens of RPMs in a dry condition before enough suction is created to draw water up.

Now if the impeller is designed/rated for a bunch of rotations on a dry housing before priming then that's probably not a big deal.  But clearly it puts more stress on the impeller than if it was below water level.

In my old I/O sterndrive boat, the impeller is deep under the engine which makes it a total PITA to service/replace but one advantage is that it's always below the water line so it's guaranteed to always be primed and never run dry (unless there's some kind of obstruction blocking the water inlet tube)

 

 

[hethj7]

Yes, that is correct. However, since moving away from the Sherwood the impeller issues seem to be a thing of the past.  Recommended interval is 50 hours.  Maybe if it were below the water line it would be longer, but I think it is a non-issue again.  

[atLakeSantee]

Being above the water line is not an issue after the air gets circulated out of the water hoses; the impeller is then fully in water. 
When first dropping the boat into the water, the suction line does contain some air; however the impeller still has water within it from prior time boat was in the water. The impeller won’t overheat itself while pumping the air bubbles though.